A terrorist gunman killed 84 people and wounded scores when he drove a heavy truck at high speed into a crowd watching Bastille Day fireworks in the French Riviera city of Nice late on Thursday.

The driver was shot dead after barrelling the truck two kilometres (1.3 miles) through the festive crowd on the palm-lined Promenade des Anglais, sending hundreds fleeing in terror and leaving the area strewn with bodies.

Authorities said they found identity papers belonging to a 31-year-old French-Tunisian citizen in the truck, as well as "guns" and "larger weapons".

In a pre-dawn address to the nation, President Francois Hollande called up military and police reservists to relieve forces worn out by an eight-month state of emergency begun after the Islamic State militant group killed 130 people in Paris. The state of emergency has been extended.

"France is filled with sadness by this new tragedy," Hollande said, noting several children were among the dead in what he said he had no doubt was an act of terrorism.

Italy boosts controls at French border crossings

Italy will boost controls at three road crossings into France and at the Ventimiglia train link between the two countries following the truck attack in nearby Nice, Italian Interior Minister Angelino Alfano said on Friday.

Death roll rises

Hollande calls up reservists

French President Francois Hollande has vowed to strengthen his country's role in the fight against the Islamic State group in Iraq and Syria after a deadly attack on Nice, which has not been claimed by any group.

"Nothing will make us yield in our will to fight terrorism. We will further strengthen our actions in Iraq and in Syria. We will continue striking those who attack us on our own soil," he said, in reference to the Islamic State group.

He also said he had called on reservists to boost the ranks of police and gendarmes. France's "operational reservists" include French citizens with or without military experience as well as former soldiers. Mr Hollande said they would in particular be used to boost "border controls".

Events cancelled

The president of the region that includes Nice has announced that the city's jazz festival, due to open on Saturday, and a Rihanna concert planned for Friday evening, have both been cancelled after the deadly truck attack.

Christian Estrosi said flags would be lowered across the city on Friday.

'A tragic paradox'

European Council president Donald Tusk says it is a "tragic paradox" that the victims of the attack in Nice were celebrating "liberty, equality and fraternity" - France's motto - on the country's national day.

Mr Tusk tweeted a photograph of himself and other European and Asian leaders standing in tribute to the Nice victims at the Asia-Europe meeting in Mongolia.

World leaders react

'I'm still shaking'

British holidaymaker Esther Serwah, 59, was staying in a hotel a short walk from the scene, writes Peter Allen in Paris.

She said she had been on her way to the Promenade des Anglais for dinner with her daughters when people started screaming at her.

Mrs Serwah, from Surrey, said:

"I was just walking to the Promenade and then I saw everybody running and I just didn't know what was going on. People were screaming at me in French but I didn't understand.

"Some people were lying on the streets dead and people were running over the bodies. Everybody was saying it's a terrorist attack. It's just horrible, horrible, horrible. I'm in shock. I'm still shaking."

'75 dead'

The ranking politician of the Alpes-Maritime department that includes Nice says the truck plowed into the crowd over a distance of more than a mile, killing 75 people and wounding 50.

Eric Ciotti said on BFM TV that police killed the driver "apparently after an exchange of gunfire."

The Paris prosecutor's office opened an investigation for "murder, attempted murder in an organised group linked to a terrorist enterprise." The probe is being handled by France's intelligence agency and judicial police.

'I'm still shaking,' says British tourist

British holidaymaker Esther Serwah, 59, was staying in a hotel a short walk from the scene, writes Peter Allen in Paris.

She said she had been on her way to the Promenade des Anglais for dinner with her daughters when people started screaming at her.

Mrs Serwah, from Surrey, said:

"I was just walking to the Promenade and then I saw everybody running and I just didn't know what was going on. People were screaming at me in French but I didn't understand.

"Some people were lying on the streets dead and people were running over the bodies. Everybody was saying it's a terrorist attack. It's just horrible, horrible, horrible. I'm in shock. I'm still shaking."

British student tells of 'terrifying' ordeal

Joel Fenster, a 23-year-old law student from north London who is in Nice for a language course, told The Telegraph how he and friend ran for cover after hearing gunshots.

“We went to watch the fireworks on the beach and then after we knew there was meant to be a concert so we were walking round to the promenade. It was a perfectly normal night,” he said, speaking from his apartment in Nice.

“Suddenly everyone started running in the opposite direction to us, and ducking down. It seemed like there was someone coming - there was a strong sense that we needed to get away. So we started running away from the beach, inland towards the old town. We heard the gunshots - initially one, then later two more."

Mr Fenster, a Cambridge University graduate, was in Nice for a one month French language course before starting a job at a law firm in London.

He said: “We ran down a road, everyone was ducking down and going into doorways. We ran into an alleyway and crouched down for about an hour. The whole time it was terrifying but didn’t quite feel real.

“We ran into a restaurant that was open, people were rushing into it from the street. At that point we thought there was a shooter running around. The police came and told the owner to turn the lights off and put the shutters down. Everyone got down on the floor, crouching below tables. There were quite a few young children, they were terrified.”

Mr Fenster said the police came back to the restaurant about half an hour later and told everyone to evacuate the building.

“We were directed to Place Massena. Police were pointing guns and telling people to empty their bags. After that we just ran home to our flat," he said.

'My daughter managed to escape'

Loupzenoui Lautur said her daughter was present when the lorry crashed into the crowd.

"She and a friend managed to escape and find refuge the spectator stands. They could hear shouting but they ran home without looking back. There were even people who escaped from the attack in their building."

The latest

At least 73 people were killed and about 100 injured on Thursday night when a lorry drove into a crowd of Bastille Day revellers in an apparent terrorist attack in Nice, David Chazan reports.

A gunman reportedly got out of the lorry and fired into the crowd on the seafront Promenade des Anglais, an area popular with tourists in the Riviera resort, leaving dead and injured people lying in the street.

He was shot dead by police but there were reports that an accomplice had fled and that guns and grenades were found in the lorry.

The local Prefecture described the slaughter as a “terrorist attack” but an interior ministry spokesman, Pierre-Henry Brandet, said it was too early to be certain of the killers’ motives.

'Children in tears'

The manager of Le Voilier Plage restaurant in Nice said:

“Just as the fireworks finished we saw a lorry drive onto the pavement. There was a massive panic there must have been somewhere between 1,000 and 1,500 people on the Promenade des Anglais. There was an awful panic, people were running everywhere. We provided a refuge for some people, mothers, children. There were people lying on the ground who were injured or worse.

'Truck was travelling at 60-70km per hour'

A local Nice Matin journalist on the scene reported: “People ran, there was panic. He drove onto the promenade and ploughed into the crowd. There is a huge amount of blood and without doubt a lot of people have been hurt.”

A witness who gave his name as Antoine said: “We were at the Neptune beach and a firework display had just finished. That is when we saw a white lorry. It was going quickly at 60-70 kilometres an hour.”

'You need to go, the police have told us to run'

Colin Srivastava told BBC News: "We were basically sitting just in front of the Old Town in Nice and saw several hundred people running towards us looking panic stricken.

"We tried to ask a few of them what the hell was going on and finally got one that said, 'You need to go, the police have told us to run'.

"Just around about the base of the hill where the castle is in Nice the police came running along and said, 'Run now'.

"We had absolutely no idea what was going on, to be honest with you.

"When we got down into the port in Nice we were told by a few people who'd obviously run faster than we had that there was the story of a lorry that had gone into the people, basically cannoned into the crowd, and there were also shots fired, which is something we didn't hear about until just now on French news."

Mayor of Nice tweets

Nice mayor Christian Estrosi, who was at the celebration when it happened, tweeted: "Dear people of Nice, the driver of a truck seems to have left dozens dead. Stay for now in your home. More info to come."

More footage of people fleeing in panic

30 people reported killed

French tv states up to 30 people have been killed.

BFM TV reported "dozens of dead" in Nice. "It's total panic," a witness told the channel by telephone. "We saw a white lorry which drove directly into people on the Promenade des Anglais. A gunman fired into the crowd before being shot by police. Perhaps they are dead, I'm not sure."